In hydrocarbon evaluations, mapping faults is essential to determine migration pathways and to establish lateral limits of reservoirs. Faults can also fragment a reservoir. Traditionally, faults are picked by hand in 2D or 3D seismic volumes as discontinuities in seismic amplitudes and seismic character on sections and time slices. This is the most time-consuming process in hydrocarbon evaluation workflows.
In recent years, there have been several attempts to automate fault interpretation. These attempts generally rely on processing seismic volumes to highlight faults followed by tracking faults in such fault-enhanced volumes. Fault-enhanced volumes show fault-related discontinuity patches that are oriented vertically and are usually much shorter than faults due to short processing windows. Patches may, however, also be caused by seismic acquisition and processing artifacts, by stratigraphic discontinuities such as multiple river channels in lower-coastal plain settings and by hydrocarbon effects. Interactive fault trackers rely on a seed fault identified by the interpreter, which makes fault tracking more reliable but is still limited by the quality of fault-enhanced volumes.
Unfortunately, seismic data volumes do not always have the quality required for fault-enhanced volumes that are suitable for automatic fault-extraction methods. This may make it necessary to revert to traditional manual interpretation. Even in cases where the fault-enhanced volumes are good enough to make automatic fault extraction work, there may still be a need to edit and/or delete the resulting faults by hand. Even with the advent of automatic fault extraction, there is a need for tools to help in the manual interpretation process by fault location “snapping,” by interactive fault tracking and by calculating fault throw, which must be underpinned by rigorous, consistent and independent assessments of fault quality.